Computerized tomography (ct) image correction using position and direction (p&amp;d) tracking assisted optical visualization

ABSTRACT

A system (11) includes a medical probe (36) for insertion into a cavity of an organ, which includes a position and direction sensor (60) and a camera (45), both operating in a sensor coordinate system (62). The system further includes a processor (44) configured to: receive, from an imaging system (21) operating in an image coordinate system (28), a three-dimensional image of the cavity including open space and tissue; receive, from the medical probe, signals indicating positions and respective directions of the medical probe inside the cavity; receive, from the camera, respective visualized locations inside the cavity; register the image coordinate system with the sensor coordinate system so as to identify one or more voxels in the image at the visualized locations, and when the identified voxels have density values in the received image that do not correspond to the open space, to update the density values of the identified voxels to correspond to the open space.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication 62/741,403, filed Oct. 4, 2018, whose disclosure isincorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates generally to medical imaging, andparticularly to updating an outdated medical image while performing aninvasive medical procedure.

BACKGROUND OF THE INVENTION

During a medical procedure, a real-time representation of an anatomyprobed by a medical device, such as by a probe tracked by a positiontracking system, can be superimposed on pre-acquired medical images soas to improve the anatomy representation. For example, U.S. PatentApplication Publication 2018/0146883 describes methods, apparatuses andcomputer program products that include receiving, from an imaging systemoperating in an image coordinate system, a three-dimensional image of abody cavity including open space and body tissue, and receiving, from amedical probe having a location sensor and inserted into the bodycavity, a signal indicating a location of a distal tip of the medicalprobe in a sensor coordinate system. The image coordinate system isregistered with the sensor coordinate system so as to identify one ormore voxels in the three-dimensional image at the indicated location,and when the identified voxels have density values in the receivedthree-dimensional image that do not correspond to the open space, thedensity values of the identified voxels are updated to correspond to theopen space.

As another example, U.S. Patent Application Publication 2014/0147027describes an imaging correction system that includes a trackedultrasonic imaging probe configured to generate imaging volumes of aregion of interest from different positions. An image compensationmodule is configured to process image signals from an ultrasound imagingdevice associated with the probe and to compare one or more ultrasoundimage volumes with a reference, such as CT images, to determine, usingan image compensation module, aberrations in ultrasonic imaging andgenerate a corrected ultrasound image for display based on compensatingfor the aberrations.

Image-guided surgery (IGS), such as described above, is a techniquewhere a computer is used to obtain a real-time correlation of thelocation of an instrument that has been inserted into a patient's bodyto a set of preoperatively obtained images (e.g., a CT or MRI scan, 3Dmap, etc.), such that the computer system may superimpose the currentlocation of the instrument on the preoperatively obtained images. Anexample of an electromagnetic IGS navigation systems that may be used inIGS procedures is the CARTO® 3 System by Biosense-Webster, Inc., ofIrvine, Calif.

In some IGS procedures, a digital tomographic scan (e.g., CT or MRI, 3Dmap, etc.) of the operative field is obtained prior to surgery. Aspecially programmed computer is then used to convert the digitaltomographic scan data into a digital map. During surgery, specialinstruments having position sensors (e.g., electromagnetic coils thatemit electromagnetic fields and/or are responsive to externallygenerated electromagnetic fields) are used to perform the procedurewhile the sensors send data to the computer indicating the currentposition of each surgical instrument. The computer correlates the datait receives from the sensors with the digital map that was created fromthe preoperative tomographic scan. The tomographic scan images aredisplayed on a video monitor along with an indicator (e.g., crosshairsor an illuminated dot, etc.) showing the real-time position of eachsurgical instrument relative to the anatomical structures shown in thescan images. The surgeon is thus able to know the precise position ofeach sensor-equipped instrument by viewing the video monitor even if thesurgeon is unable to directly visualize the instrument itself at itscurrent location within the body.

While IGS navigation systems provide useful views and information duringa surgical procedure, a surgeon may also desire real-time photographsand video of an anatomical structure being operated on. In such cases,an endoscope may be deployed to the surgical site with the aid of IGSnavigation in order to capture images of the anatomical structure; andmay also be paired with or otherwise deployed with other surgicalinstruments, such as cutting instruments, ablation instruments, dilationcatheters, etc. Photographic images and video captured in this mannermay be more useful than IGS navigation images, which may only providegeneralized and simulated images. Alternatively, photographic images andvideo captured in this manner may provide a useful supplement to IGSnavigation images.

Images captured by a conventional endoscope may also be somewhat limitedas compared to direct visual observation by a surgeon, as imagescaptured with a conventional endoscope may be limited to two-dimensional(2D) representations of an anatomical structure. Operation such ascutting, ablating, dilating, etc. may be performed using a combinationof 2D endoscopy and IGS navigation, neither of which can provide thesense of depth perception available with true three-dimensional (3D)observation. Manipulating and operating surgical tools without thebenefit of 3D observation can increase the time spent positioning tools;and can increase the possibility of error. While some 3D endoscopiccameras exist, they have a high complexity and cost; and may have rigidand inflexible portions that make them difficult or impossible to usefor some procedures.

Implementations having both flexibility and 3D features may requireexpensive and fragile fiber optic components to transfer captured imagesfrom a distal camera to a proximal viewer. As a result, conventionaloptions for 3D endoscopy may be expensive, limited in availablefeatures, and unsuitable for high volume use and disposability.

While several systems and methods have been made and used in surgicalprocedures, it is believed that no one prior to the inventors has madeor used the invention described in the appended claims.

SUMMARY OF THE INVENTION

An embodiment of the present invention provides a system including amedical probe, a position and direction sensor, a camera, and aprocessor. The medical probe is configured to be inserted into a cavityof an organ of a patient. The position and direction sensor is in themedical probe and is operating in a sensor coordinate system. The camerais in a distal edge of the medical probe and is operating in a sensorcoordinate system. The processor configured to: (a) receive, from animaging system operating in an image coordinate system, athree-dimensional image of the cavity including open space and organtissue, (b) receive, from the medical probe, signals indicatingpositions and respective directions of the distal edge of the medicalprobe inside the cavity, (c) receive, from the camera of the probe,respective visualized locations inside the cavity, (d) register theimage coordinate system with the sensor coordinate system so as toidentify one or more voxels in the three-dimensional image at thevisualized locations, and (e) when the identified voxels have densityvalues in the received three-dimensional image that do not correspond tothe open space, to update the density values of the identified voxels tocorrespond to the open space.

In some embodiments, the imaging system includes a computed tomographyscanner.

In some embodiments, the position and direction sensor includes amagnetic field sensor.

In an embodiment, the processor is configured to form a correspondencebetween the density values visual effects, wherein a given visual effectcorresponds to a given density value indicating the open space. Inanother embodiment, the visual effects are selected from a groupconsisting of colors, shadings and patterns.

In some embodiments, the processor is configured to present thethree-dimensional image on a display using the visual effects. In otherembodiments, the given visual effect includes a first given visualeffect, and, prior to updating the density values, the processor isconfigured to present the three-dimensional image by presenting, using asecond given visual effect different from the first given visual effect,the one or more identified voxels.

In an embodiment, upon updating the density values, the processor isconfigured to present the three-dimensional image by presenting, usingthe first given visual effect, the one or more identified voxels. Inanother embodiment, the processor is configured to, using a multi-viewtriangulation model, extract from the visual signals a distance of alocation from the camera.

There is additionally provided, in accordance with an embodiment of thepresent invention, a method, including receiving, from an imaging systemoperating in an image coordinate system, a three-dimensional image of acavity of an organ of a patient including open space and organ tissue.Signals indicating positions and respective directions of a distal edgeof the medical probe inside the cavity, and respective visualizedlocations inside the cavity, are received from a medical probe having aposition and direction sensor and a camera, wherein the probe operatesin a sensor coordinate system and inserted into the cavity. The imagecoordinate system is registered with the sensor coordinate system so asto identify one or more voxels in the three-dimensional image at thevisualized locations. When the identified voxels have density values inthe received three-dimensional image that do not correspond to the openspace, the density values of the identified voxels are updated tocorrespond to the open space.

There is further provided, in accordance with an embodiment of thepresent invention, computer software product, operated in conjunctionwith a probe that is configured for insertion into a cavity of an organof a patient and includes a position and direction sensor operating in asensor coordinate system and a camera in a distal edge of the medicalprobe operating in a sensor coordinate system, and the product includinga non-transitory computer-readable medium, in which program instructionsare stored, which instructions, when read by a computer, cause thecomputer to (a) receive, from an imaging system operating in an imagecoordinate system, a three-dimensional image of the cavity includingopen space and organ tissue, (b) receive, from the medical probe,signals indicating positions and respective directions of the distaledge of the medical probe inside the cavity, (c) receive respectivevisualized locations the wall of the cavity, (d) register the imagecoordinate system with the sensor coordinate system so as to identifyone or more voxels in the three-dimensional image at the visualizedlocations, and (e) when the identified voxels have density values in thereceived three-dimensional image that do not correspond to the openspace, to update the density values of the identified voxels tocorrespond to the open space.

There is furthermore provided, in accordance with an embodiment of thepresent invention, a three-dimensional (3D) imaging system including anendoscope and a processor. The endoscope includes: (i) a shaft having adistal tip, the shaft adapted to be inserted into a patient andpositioned at a surgical site of the patient, (ii) a position sensorproximate to the distal tip and configured to produce a set of positionsignals based on the location of the endoscope during use, and (iii) animaging module positioned at the distal tip and operable to capture aset of image data of the surgical site, wherein the set of image dataincludes one or more two-dimensional (2D) images. The processor iscommunicatively coupled with the endoscope and configured to: (i)receive the set of image data and the set of position signals from theendoscope, (ii) determine a set of perspective data based on the set ofposition signals, wherein the set of perspective data indicates thelocation of the endoscope during capture of each of the one or more 2Dimages, (iii) perform an image depth analysis to determine a set of 3Dcharacteristics for each of the one or more 2D images, wherein the setof 3D characteristics includes a depth of pixels, (iv) create a set of3D image data based on the one or more 2D images and the set of 3Dcharacteristics, and (v) associate the set of perspective data with theset of 3D image data, wherein the image depth analysis includes atechnique selected from the group consisting of: (i) a wavefrontsampling technique performed on a single image of the one or more 2Dimages, and (ii) a passive stereo vision technique performed on a set oftwo images of the one or more 2D images, wherein each of the set of twoimages are associated with the same perspective data.

In some embodiments, the imaging module includes: (i) a single lens,(ii) an aperture plate positioned between a first side of the singlelens and the surgical site, the aperture plate including one or moreapertures that are offset from the optical axis of the single lens, and(iii) an image pane positioned at a second side of the single lens toreceive reflected light from the surgical site via the one or moreapertures and the single lens, wherein the image pane is configured toproduce the set of image data based on the reflected light.

In some embodiments, (i) the one or more apertures include at least twoapertures positioned on the aperture plate and offset from the opticalaxis of the single lens, and (ii) the aperture plate has a fixedposition and orientation relative to the lens.

In an embodiment, (i) the one or more apertures include a singleaperture positioned on the aperture plate offset from the optical axisof the single lens, (ii) the aperture plate is operable to rotate aroundits circular axis relative to the lens during image capture.

In another embodiment, the processor is configured to, when performingthe image depth analysis: (i) identify, within the set of image data,two or more unfocused images of the surgical site, (ii) determine aspatial relationship between the two or more unfocused images of thesurgical site, and (iii) determine the depth of pixels of the set ofimage data based on the spatial relationship between the two or moreunfocused images.

In some embodiments, the imaging module includes two or more cameras,and wherein each of the two or more cameras is: (i) staticallypositioned relative to every other camera of the two or more cameras,(ii) oriented to have a parallel optical axis with every other camera ofthe two or more cameras.

In some embodiments, the processor is further configured to, whenperforming the image depth analysis, (i) identify a point in a firstimage of the set of image data, wherein the point includes a portion ofthe surgical site that is present within both the first image capturedby a first camera of the two or more cameras and within a second imagecaptured by a second camera of the two or more cameras, (ii) identifythe point in the second image, (iii) determine a displacement of thepoint from the first image to the second image, and (iv) determine thedepth of pixels for the point based on the displacement.

In an embodiment, the processor is further configured to, whenidentifying the point in the second image, (i) determine an Epipolarline for the first image and the second image based on the staticposition of the first camera relative to the second camera, and (ii)search for the point in the second image along the Epipolar line whileexcluding portions of the second image that do not fall along theEpipolar line.

In another embodiment, the processor is further configured to: (i)associate the set of 3D image data and the set of perspective data witha coordinate system of an image guided surgery system, and (ii) displaythe set of 3D image data during an image guided surgery navigationprocedure based upon the association with the coordinate system.

In an embodiment, (i) the position sensor is configured to produce theset of position signals based on the location and orientation of theendoscope during use, (ii) the set of perspective data indicates thelocation and orientation of the endoscope during capture of the set ofimage data, and (iii) the processor is further configured to provide theset of 3D image data and the set of perspective data to an image guidedsurgery navigation system.

In another embodiment, the processor is further configured to: (i)receive an input from a user defining a perspective relative to thesurgical site, (ii) determine a first portion of the set of 3D imagedata depicting the surgical site from the perspective based onidentifying the perspective within the set of perspective data, and(iii) display the first portion of the set of 3D image data on adisplay.

In yet another embodiment, the processor is further configured to: (i)receive an indirect 3D scan of the surgical site and a set of scanperspective data associated with the indirect 3D scan, (ii) determine asecond portion of the indirect 3D scan depicting the surgical site fromthe perspective based on identifying the perspective within the set ofscan perspective data, and (iii) display the first portion of the set of3D image data and the second portion of the indirect 3D scan on thedisplay simultaneously.

In a further embodiment, (i) the indirect 3D scan of the surgical siteincludes pre-operatively captured image data, and (ii) the set of 3Dimage data includes post-operatively captured image data.

In an embodiment, (i) the indirect 3D scan of the surgical site includespre-operatively captured image data, (ii)the set of 3D image dataincludes pre-operatively captured image data, and (iii) the processor isfurther configured to: (A) receive a scan adjustment input from a user,and (B) reconfigure the association between the indirect 3D scan of thesurgical site and the set of scan perspective data based on the scanadjustment input.

There is additionally provided, in accordance with an embodiment of thepresent invention, a method for three-dimensional (3D) imaging includingdeploying a distal tip of an endoscope to a surgical site of a patient,the distal tip including: (i) an imaging module operable to captureimage data of the surgical site, wherein captured image data includesone or more two-dimensional (2D) images, and (ii) a position sensorproximate to the distal tip and configured to produce position signalsbased on the location of the endoscope. A set of image data is receivedfrom the imaging module and a set of position signals from the positionsensor. A set of perspective data is determined based on the set ofposition signals, wherein the set of perspective data indicates thelocation of the endoscope during capture of each of the one or more 2Dimages. An image depth analysis is performed to determine a set of 3Dcharacteristics for each of the one or more 2D images, wherein the setof 3D characteristics includes a depth of pixels. A set of 3D image datais created based on the one or more 2D images and the set of 3Dcharacteristics, and the set of perspective data is associated with theset of 3D image data, wherein the image depth analysis includes atechnique selected from the group consisting of: (i) a wavefrontsampling technique performed on a single image of the one or more 2Dimages, and (ii) a passive stereo vision technique performed on a set oftwo images of the one or more 2D images, wherein each of the set of twoimages are associated with the same perspective data.

Another embodiment of the present invention provides an image guidedsurgery (IGS) navigation system including a processor, a memory, and adisplay, the processor configured to: (a) receive a set of image dataproduced by a tracked endoscope, the set of image data including one ormore two-dimensional (2D) images; (b) receive a set of perspective dataproduced by the tracked endoscope, wherein the set of perspective dataindicates a location of the tracked endoscope during capture of the setof image data; (c) perform an image depth analysis to determine a set of3D characteristics of the set of image data, wherein the set of 3Dcharacteristics includes a depth of pixels in the one or more 2D images;(d) create a set of 3D image data based on the one or more 2D images andthe set of 3D characteristics; (e) associate the set of perspective datawith the set of 3D image data; and (f) cause the display to show the setof 3D image data from a selected perspective based on the set ofperspective data including the selected perspective.

The present invention will be more fully understood from the followingdetailed description of the embodiments thereof, taken together with thedrawings in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B, referred to collectively as FIG. 1 , are schematicpictorial illustrations of a medical system configured to correct anoutdated computerized tomography (CT) image while performing an invasivemedical procedure, in accordance with an embodiment of the presentinvention;

FIG. 2 is a flow chart that schematically illustrates a method ofcorrecting an outdated CT image, in accordance with an embodiment of thepresent invention;

FIG. 3 is a schematic pictorial illustration showing an image slice of athree-dimensional CT image, in accordance with an embodiment of thepresent invention;

FIG. 4 is a schematic detail view showing a distal end of a probeinserted into a sinus cavity, in accordance with an embodiment of thepresent invention;

FIG. 5 is a schematic pictorial illustration showing a region ofinterest of the CT image slice of FIG. 3 prior to updating the CT image,in accordance with an embodiment of the present invention;

FIG. 6 is a schematic pictorial illustration showing the region ofinterest of the CT image slice of FIG. 5 subsequent to updating the CTimage, in accordance with an embodiment of the present invention;

FIG. 7 depicts a schematic view of an exemplary surgery navigationsystem being used on a patient seated in an exemplary medical procedurechair, in accordance with another embodiment of the present invention;

FIG. 8 depicts a perspective view of an exemplary instrument usable withthe surgery navigation system of FIG. 7 , in accordance with anembodiment of the present invention;

FIG. 9A depicts a perspective view of an exemplary distal tip of theinstrument of FIG. 8 having a single imaging device, in accordance withan embodiment of the present invention;

FIG. 9B depicts an elevation view of the distal tip of FIG. 9A, inaccordance with an embodiment of the present invention;

FIG. 10A depicts a perspective view of the distal tip of FIG. 9A with anirrigation diverter removed to show an irrigation channel, in accordancewith an embodiment of the present invention;

FIG. 10B depicts an elevation view of the distal tip of FIG. 9A with anirrigation diverter removed to show an irrigation channel, in accordancewith an embodiment of the present invention;

FIG. 11 depicts a schematic diagram of an exemplary static samplingaperture configuration for the imaging device of FIG. 9A, in accordancewith an embodiment of the present invention;

FIG. 12 depicts a schematic diagram of an exemplary active samplingaperture configuration for the imaging device of FIG. 9A;

FIG. 13 depicts a set of exemplary steps that may be performed toproduce a three-dimensional image model using the imaging device of FIG.9A, in accordance with an embodiment of the present invention;

FIG. 14A depicts a perspective view of an exemplary alternative distaltip of the instrument of FIG. 8 having a set of imaging devices;

FIG. 14B depicts an elevation view of the distal tip of FIG. 14A, inaccordance with an embodiment of the present invention;

FIG. 15A depicts a side diagrammatic view of an exemplary set ofoverlapping fields of view of the set of imaging devices of FIG. 14A, inaccordance with an embodiment of the present invention;

FIG. 15B depicts a top-down diagrammatic view of the set of overlappingfields of view of FIG. 14A, in accordance with an embodiment of thepresent invention;

FIG. 16 depicts a set of exemplary steps that may be performed toproduce a three-dimensional image model using the set of imaging devicesof FIG. 14A, in accordance with an embodiment of the present invention;

FIG. 17 depicts a diagram illustrating a relationship between disparityand depth in stereo imaging;

FIG. 18 depicts a diagram illustrating an epipolar line in stereoimaging, in accordance with an embodiment of the present invention; and

FIG. 19 depicts a flowchart of a set of steps that may be performed toproduce and use a three-dimensional image model with the surgerynavigation system of FIG. 7 .

The drawings are not intended to be limiting in any way, and it iscontemplated that various embodiments of the invention may be carriedout in a variety of other ways, including those not necessarily depictedin the drawings. The accompanying drawings incorporated in and forming apart of the specification illustrate several aspects of the presentinvention, and together with the description serve to explain theprinciples of the invention; it being understood, however, that thisinvention is not limited to the precise arrangements shown.

DETAILED DESCRIPTION OF EMBODIMENTS

Overview

According to one aspect of the present invention, an intra-operativemedical imaging system, such as a computerized tomography (CT) imagingsystem, is a modality typically unavailable in clinics that perform ear,nose and throat (ENT) procedures. Therefore, an ENT physician performinga procedure usually relies on previously acquired medical images such asCT images. The CT images can be used to generate a real-time guide(i.e., a “map”) that enables the physician performing the ENT medicalprocedure to navigate a medical probe within a volume of interest insidea cavity in the head of a patient.

However, in some cases, for example, during or after a surgical ENTprocedure, such as shaving an obstructing cartilage or bone at a wall ofthe cavity, the CT image no longer reflects the true anatomy of thecavity.

Embodiments of the present invention that are described hereinafterprovide systems and methods for updating an outdated medical image suchas an outdated CT image of a cavity of an organ of a patient, the CTimage also being referred to herein as a three-dimensional image.

In some embodiments, during an updating procedure, a camera located at adistal tip of a medical probe and operating in a probe coordinate systemvisualizes locations inside a cavity comprising open space and organtissue. A processor estimates the locations using visualization fromdifferent positions and directions that the camera provides. Thedifferent positions and directions are derived by the processor fromsignals received from a position and direction (P&D) sensor installed ata distal tip of the medical probe.

Using a multi-view triangulation model, the processor reconstructs thevisualized locations by reconstructing distances of the locations fromthe camera. Such multi-view triangulation model can use, for example, aMATLAB® function named “triangulateMultiview,” which returns locationsof 3D world points that correspond to points matched across multipleimages taken with a P&D calibrated camera.

In order for the CT images to reflect an up to date visualized (i.e.,true) anatomy of the cavity, the processor registers the coordinatesystem associated with the CT imaging system with the coordinate systemassociated with the medical probe (e.g., with the sensor coordinatesystem). The registration enables the processor to identify one or morevoxels in the three-dimensional image at the indicated locations, andwhen the identified voxels have density values in the receivedthree-dimensional image that do not correspond to the newly formed openspace (formed, for example, by an ENT shaving procedure) as visualizedby the camera, and as estimated by the processor using the multi-viewtriangulation model, the density values of the identified voxels areupdated to correspond to the new open space.

Medical imaging systems typically use different visual effects topresent open space and body tissue. For example, a CT system may presentopen space in black, hard body tissue in white and soft body tissue in(various shades of) gray. Since the camera, being located at the distaledge of the medical probe, can only optically image wall tissue throughopen space, systems implementing embodiments of the present inventioncan correct, in an updated three-dimensional (3D) CT image, anyoptically imaged locations of the cavity that are not presented as openspace. In addition, if the camera has entered a location that was notpreviously open space, embodiments of the present invention can alsopresent the entered location as open space in the updated 3D image.

Other aspects of the disclosed invention provide imaging techniques,such as wavefront sampling and passive stereo vision, that are used toproduce 3D image data and 3D models from single camera and multi camera2D imaging systems. Such techniques are implemented to produce 3Dcapable imaging systems with small size and low complexity compared to3D imaging systems with independent dynamically focused cameras. Withreduced size and power requirements, such imaging techniques (e.g.,systems) are implemented at a distal tip of a surgical instrument havinga static or flexible shaft, and may be used to produce 3D imaging ofsurgical sites within the human body. Such 3D imaging may be used toproduce composite image sets usable during IGS navigation, to providecomparisons of pre-operative image sets, and to provide comparisons ofpost-operative image sets.

In some embodiments, a 3D endoscopy imaging system is provided, whichcomprise (a) an endoscope comprising a position sensor, and an imagingmodule positioned at the distal tip of the endoscope and operable tocapture a set of image data of the surgical site, wherein the set ofimage data comprises one or more two-dimensional (2D) images, and (b) aprocessor communicatively coupled with the endoscope and configured to:

(i) receive the set of image data and the set of position signals fromthe endoscope,

(ii) determine a set of perspective data based on the set of positionsignals, wherein the set of perspective data indicates the location ofthe endoscope during capture of each of the one or more 2D images,

(iii) perform an image depth analysis to determine a set of 3Dcharacteristics for each of the one or more 2D images, wherein the setof 3D characteristics comprises a depth of pixels,

(iv) create a set of 3D image data based on the one or more 2D imagesand the set of 3D characteristics, and

(v) associate the set of perspective data with the set of 3D image data;

wherein the image depth analysis comprises a technique selected from thegroup consisting of:

(i) a wavefront sampling technique performed on a single image of theone or more 2D images, and

(ii) a passive stereo vision technique performed on a set of two imagesof the one or more 2D images, wherein each of the set of two images areassociated with the same perspective data.

Embodiments of the present invention disclose medical image, such as CTimage, correction using a P&D tracking assisted visualization techniqueof cavity locations. Using the embodiments may eliminate the need forrepeating an imaging procedure, such as a CT imaging procedure,typically requiring a large and expensive operation facility.

CT Image Correction Using P&D Tracking Assisted Optical Visualization

The following description of certain examples of the invention shouldnot be used to limit the scope of the present invention. Other examples,features, aspects, embodiments, and advantages of the invention willbecome apparent to those skilled in the art from the followingdescription, which is by way of illustration, one of the best modescontemplated for carrying out the invention. As will be realized, theinvention is capable of other different and obvious aspects, all withoutdeparting from the invention. Accordingly, the drawings and descriptionsshould be regarded as illustrative in nature and not restrictive.

It will be appreciated that the terms “proximal” and “distal” are usedherein with reference to a clinician gripping a handpiece assembly.Thus, an end effector is distal with respect to the more proximalhandpiece assembly. It will be further appreciated that, for convenienceand clarity, spatial terms such as “top” and “bottom” also are usedherein with respect to the clinician gripping the handpiece assembly.However, surgical instruments are used in many orientations andpositions, and these terms are not intended to be limiting and absolute.

It is further understood that any one or more of the teachings,expressions, versions, examples, etc. described herein may be combinedwith any one or more of the other teachings, expressions, versions,examples, etc. that are described herein. The following-describedteachings, expressions, versions, examples, etc. should therefore not beviewed in isolation relative to each other. Various suitable ways inwhich the teachings herein may be combined will be readily apparent tothose skilled in the art in view of the teachings herein. Suchmodifications and variations are intended to be included within thescope of the claims.

FIGS. 1A and 1B, referred to collectively as FIG. 1 , are schematicpictorial illustrations of a medical system 11 configured to correct anoutdated computerized tomography (CT) image while performing an invasivemedical procedure, in accordance with an embodiment of the presentinvention. In the example shown in FIG. 1 , medical system 11 comprisesa medical imaging system comprising a mobile CT scanner 21, a controlconsole 34, and a medical probe 36. In embodiments described herein, itis assumed that medical probe 36 is used for ENT diagnostic ortherapeutic treatment, such as minimally invasive catheter-based sinussurgery on a patient 26. Alternatively, medical probe 36 may be used,mutatis mutandis, for other therapeutic and/or diagnostic purposes.

As shown in FIG. 1A, prior to performing an invasive medical procedureon patient 26, CT scanner 21 generates electrical signals comprisingimage data for a lumen (e.g., a nasal cavity or a paranasal sinus) ofthe patient, and conveys the generated image data to control console 34.Computed tomography scanner 21 generates the image data in an imagecoordinate system 28 comprising an X-axis 31, a Y-axis 33 and a Z-axis35.

As shown in FIG. 1B, medical probe 36 comprises a handle 38 that anoperator 43 can grasp and manipulate in order to insert a distal end 41of the medical probe into a lumen, such as a nasal cavity or a paranasalsinus, of patient 26.

Distal end 41 comprises a camera 45 generating image data in response toa scene viewed by the camera. Distal end 41 also comprises a magneticfield sensor 60, which, as described below, generates signals providingthe position and orientation of the distal end. In the configurationshown in FIG. 1 , control console 34 comprises a processor 44 thatconverts the image data received from camera 45 into an image 46, andpresents the image as information regarding the medical procedure on adisplay 48.

Based on the signals received from medical probe 36 and other componentsof medical system 20, control console 34 drives display 48 to updateimage 46 in order to present a current position of distal end 41 in thepatient's head, as well as status information and guidance regarding themedical procedure that is in progress. Processor 44 stores datarepresenting image 46 in a memory 50. In some embodiments, operator 40can manipulate image 46 using one or more input devices 52.

Processor 44 typically comprises a general-purpose computer, withsuitable front end and interface circuits for receiving signals frommedical probe 36 and controlling the other components of control console34. Processor 44 may be programmed in software to carry out thefunctions that are described herein. The software may be downloaded tocontrol console 34 in electronic form, over a network, for example, orit may be provided on non-transitory tangible media, such as optical,magnetic or electronic memory media. Alternatively, some or all of thefunctions of processor 44 may be carried out by dedicated orprogrammable digital hardware components.

In embodiments described herein, medical system 11 uses magneticposition sensing to determine position and direction coordinates ofdistal end 41 of medical probe 36 inside patient 26. To implementmagnetic based position and direction sensing, control console 34comprises a driver circuit 56 which drives field generators 58 togenerate magnetic fields within the probed organ of patient 26.Typically, field generators 58 comprise coils, which are placed belowthe patient at known positions external to patient 26. These coilsgenerate magnetic fields in a predefined working volume that contains alumen such as a paranasal sinus. Magnetic field sensor 60 (also referredto herein as position and direction (P&D) sensor 60) within distal end41 of medical probe 36 generates electrical signals in response to themagnetic fields from the coils, thereby enabling processor 44 todetermine the position and the direction of distal end 41 within theworking volume.

Magnetic position tracking techniques are described, for example, inU.S. Pat. Nos. 5,391,199, 6,690,963, 5,443,489, 6,788,967, 5,558,091,6,172,499 and 6,177,792, whose disclosures are incorporated herein byreference. The signals generated by magnetic field sensor 60 indicatethe current location of distal end 41 in a sensor coordinate system 62defined by the positions of generators 58, and system 62 is assumed tocomprise an X-axis 64, a Y-axis 66 and a Z-axis 68. In the example shownin FIG. 1 , X-axis 64 generally corresponds to X-axis 31, Y-axis 66generally corresponds to Y-axis 33 and Z-axis 68 generally correspondsto Z-axis 35. Such systems and techniques are similar or the same asthose described in connection with other aspects of the inventiondescribed in connection with FIG. 7 .

In embodiments described herein, medical system 11 uses camera 45 toimage portions of a cavity. The positions from which camera 45 isimaging the cavity, as well as the respective directions the camera isaiming at are derived using sensor 60, as described above. Based on theP&D tracking and using a multi-view triangulation model, processor 44 isable to determine (i) a location of portions of the walls of the cavitywherein the distal end is situated, and (ii) locations between theimaged location on the cavity wall and the camera, including camera 45itself, which are all in open space, and to update the CT imagesaccordingly.

FIG. 2 is a flow chart that schematically illustrates a method ofcorrecting an outdated CT image, and FIGS. 3, 4, 5, and 6 are schematicfigures illustrating the method, in accordance with an embodiment of thepresent invention. In an acquiring step 80, processor 44 acquires imagedata from CT scanner 21, stores the image data to memory 50, andgenerates, based on the acquired image data, a three-dimensional image.Step 80 is typically performed prior to the updating CT image procedureto be performed on patient 26.

FIG. 3 is a schematic pictorial illustration showing an image slice 101of a three-dimensional computed tomography image that may be acquired instep 80. Processor 44 generates image slice 101 in response to receivingthe image data from CT scanner 21. In operation, processor 44 typicallyincorporates image slice 101 into image 46.

In the example shown in FIG. 3 , image slice 101 comprises atwo-dimensional “slice” of a head 103 of patient 26. As indicated by alegend 106, image slice 101 comprises voxels 105 of thethree-dimensional image that correspond to three-dimensional locationsin the computed tomography image of head 103. Processor 44 typicallypresents each given voxel 105 using different a visual effect thatcorresponds to the density detected at the three-dimensional locationcorresponding to the given voxel. Examples of densities include, but arenot limited to, open space, hard organ tissue and soft organ tissue, andexamples of visual effects include, but are not limited to, colors,shadings (e.g., different shades of gray) and patterns (e.g., gradients,pictures, textures, lines, dots and boxes).

As indicated by a legend 107, voxels 105 can be differentiated byappending a letter to the identifying numeral, so that the voxelscomprise voxels 105A-105C. In the example shown in FIG. 3 , voxels 105Aindicate open space and are presented in black, voxels 105B indicatehard organ tissue (e.g., bone) and are presented in white, and voxels105C indicate soft tissue (e.g., fat, muscle cartilage and brain tissue)and are presented in gray. While embodiments herein describe image slice101 comprising voxels 105 with three different visual effects (i.e.voxels 105A-105C), presenting the voxels with any number of visualeffects representing any number of densities is considered to be withinthe spirit and scope of the present invention.

Image slice 101 also comprises a region of interest 109. As described inthe description referencing FIGS. 5 and 6 hereinbelow, region ofinterest 109 includes cavity wall 47 locations having an outdated CTvalue (i.e., density value) that processor 44 can update usingembodiments described herein.

Returning to the flowchart, to initiate the updating procedure, operator43 manipulates handle 38 so that, in an insertion step 82, distal end 41enters a cavity of an organ of patient 26. It will be understood thatthere is typically a delay, which may be days or even weeks, betweensteps 80 and 82.

Next, in a registration step 84, processor 44 registers image coordinatesystem 28 with sensor 60 coordinate system 62. The registration may beperformed by any suitable process known in the art. Upon performing theregistration, each three-dimensional position indicated by a signalgenerated by magnetic field sensor 60 corresponds to one or more voxelsin the CT images that were acquired in step 80.

In a receiving visual signal step 86, processor 44 receives visualsignals from camera 45 indicating a location of cavity wall 47, and inan identification step 88, the processor uses the registration and themulti-view triangulation model to identify one or more voxels in the CTimages that correspond to the indicated location.

FIG. 4 is a schematic detail view showing distal end 41 inserted into asinus cavity 111. Camera 45 in distal end 41 acquires images of cavitywall 47 from different perspectives as the distal end moves. Based onthe visual signals of wall 47 that camera 45 acquires, and, as notedabove, using the multi-view triangulation model, processor 44 estimatesa location 47A of the cavity wall. It will be understood that anylocation on the respective line of sight of camera 45 to location 47A,such as location 49, as well as the location of camera 45 itself, has tobe an open space inside the cavity.

Returning to the flowchart, in a first comparison step 90, if any of theone or more identified voxels have an outdated CT density value i.e., oftissue instead of a (newly formed by an ENT procedure) open space, thenin a correction step 92, processor 44 corrects the outdated voxel(s)values to represent the voxels as a (newly formed) open space. Forexample, if a given identified voxel has a CT density outdated valuecorresponding to hard or soft tissue then processor 44 can update thedensity value to correspond to the open space. If in step 90 none of theone or more identified voxels have an outdated CT value, then the methodcontinues with step 94.

In embodiments of the present invention, updating the one or moreupdated voxels in an image slice updates the three-dimensional computedtomography image stored in memory 50.

After completion of step 92, control proceeds to a second comparisonstep 94.

In second comparison step 94, if operator 40 has completed the updatingprocedure, i.e., the operator has sufficiently inspected cavity 47 orother cavities, then the method ends. However, if operator 40 has notyet completed the updating procedure, then the method continues withstep 86.

FIG. 5 is a schematic pictorial illustration showing region of interest118 of image slice 101 prior to updating the computed tomography image,as is acquired in step 80. In the example shown in FIG. 5 , anobstructing bone 120 comprises voxels 105B (i.e., dense bone)surrounding an inner region of voxels 105A (i.e., a hollow region of thebone growth), and voxels 105C comprise soft tissue.

FIG. 6 is a schematic pictorial illustration showing region of interest118 of image slice 101 subsequent to updating the computed tomographyimage, i.e., after completion of the steps of the flowchart of FIG. 2 .As shown in FIG. 6 , region of interest 118 comprises updated regions150. Regions 150 comprise regions which processor 44 estimated are newlyformed open space based on visualization from camera 45 and using themulti-view triangulation model. Regions 150 were formed, for example, byan ENT shaving procedure that removed some of the obscuring bone 120 inFIG. 5 .

Display 48 typically presents a subset of voxels 105 that processor 44can update during an updating procedure using embodiments describedherein. As described supra, image slice 101 comprises a two-dimensional“slice” of the three-dimensional image that processor 44 generates inresponse to receiving the image data from mobile computed tomographyscanner 21. Since operator moves distal end 41 in a three-dimensionalspace (i.e., three-dimensional coordinate systems 28 and 62), it will beunderstood that there can be additional voxels 105 (i.e., not includedin the two-dimensional image slice currently being presented on display48) whose respective density values are updated by processor 44 inresponse to detected cavity wall 47 locations by camera 45.

Exemplary Image Guided Surgery Navigation System

According to another aspect of the invention, when performing a medicalprocedure within a head (H) of a patient (P), it may be desirable tohave information regarding the position of an instrument within the head(H) of the patient (P), particularly when the instrument is in alocation where it is difficult or impossible to obtain an endoscopicview of a working element of the instrument within the head (H) of thepatient (P).

FIG. 7 shows an exemplary IGS navigation system (10) enabling an ENTprocedure to be performed using image guidance, in accordance with anembodiment of the present invention. In addition to or in lieu of havingthe components and operability described herein IGS navigation system(10) may be constructed and operable in accordance with at least some ofthe teachings of U.S. Pat. No. 7,720,521, entitled “Methods and Devicesfor Performing Procedures within the Ear, Nose, Throat and ParanasalSinuses,” issued May 18, 2010, the disclosure of which is incorporatedby reference herein; and U.S. Pat. Pub. No. 2014/0364725, entitled“Systems and Methods for Performing Image Guided Procedures within theEar, Nose, Throat and Paranasal Sinuses,” published Dec. 11, 2014, thedisclosure of which is incorporated by reference herein.

IGS navigation system (10) of the present example comprises a fieldgenerator assembly (20), which comprises set of magnetic fieldgenerators (24) that are integrated into a horseshoe-shaped frame (22).Field generators (24) are operable to generate alternating magneticfields of different frequencies around the head (H) of the patient (P).A navigation guidewire (40) is inserted into the head (H) of the patient(P) in this example. Navigation guidewire (40) may be a standalonedevice or may be positioned on an end effector or other location of amedical instrument such as a surgical cutting instrument or dilationinstrument. In the present example, frame (22) is mounted to a chair(30), with the patient (P) being seated in the chair (30) such thatframe (22) is located adjacent to the head (H) of the patient (P). Byway of example only, chair (30) and/or field generator assembly (20) maybe configured and operable in accordance with at least some of theteachings of U.S. Pub. No. 2018/0310886, entitled “Apparatus to SecureField Generating Device to Chair,” published Nov. 1, 2018, thedisclosure of which is incorporated by reference herein.

IGS navigation system (10) of the present example further comprises aprocessor (12), which controls field generators (24) and other elementsof IGS navigation system (10). For instance, processor (12) is operableto drive field generators (24) to generate alternating electromagneticfields; and process signals from navigation guidewire (40) to determinethe location of a sensor in navigation guidewire (40) within the head(H) of the patient (P). Processor (12) comprises a processing unit(e.g., a set of electronic circuits arranged to evaluate and executesoftware instructions using combinational logic circuitry or othersimilar circuitry) communicating with one or more memories. Processor(12) of the present example is mounted in a console (18), whichcomprises operating controls (14) that include a keypad and/or apointing device such as a mouse or trackball. A physician uses operatingcontrols (14) to interact with processor (12) while performing thesurgical procedure.

Navigation guidewire (40) includes a sensor (not shown) that isresponsive to positioning within the alternating magnetic fieldsgenerated by field generators (24). A coupling unit (42) is secured tothe proximal end of navigation guidewire (40) and is configured toprovide communication of data and other signals between console (18) andnavigation guidewire (40). Coupling unit (42) may provide wired orwireless communication of data and other signals.

In the present example, the sensor of navigation guidewire (40)comprises at least one coil at the distal end of navigation guidewire(40). When such a coil is positioned within an alternatingelectromagnetic field generated by field generators (24), thealternating magnetic field may generate electrical current in the coil,and this electrical current may be communicated along the electricalconduit(s) in navigation guidewire (40) and further to processor (12)via coupling unit (42). This phenomenon may enable IGS navigation system(10) to determine the location of the distal end of navigation guidewire(40) or other medical instrument (e.g., dilation instrument, surgicalcutting instrument, etc.) within a three-dimensional space (i.e., withinthe head (H) of the patient (P), etc.). To accomplish this, processor(12) executes an algorithm to calculate location coordinates of thedistal end of navigation guidewire (40) from the position relatedsignals of the coil(s) in navigation guidewire (40). While the positionsensor is located in guidewire (40) in this example, such a positionsensor may be integrated into various other kinds of instruments,including those described in greater detail below.

Processor (12) uses software stored in a memory of processor (12) tocalibrate and operate IGS navigation system (10). Such operationincludes driving field generators (24), processing data from navigationguidewire (40), processing data from operating controls (14), anddriving display screen (16). In some implementations, operation may alsoinclude monitoring and enforcement of one or more safety features orfunctions of IGS navigation system (10). Processor (12) is furtheroperable to provide video in real time via display screen (16), showingthe position of the distal end of navigation guidewire (40) in relationto a video camera image of the patient's head (H), a scan image (e.g.,CT, MRI, or other X-ray or indirect imaging method) of the patient'shead (H), and/or a computer-generated three-dimensional model of theanatomy within and adjacent to the patient's nasal cavity. Displayscreen (16) may display such images simultaneously and/or superimposedon each other during the surgical procedure. Such displayed images mayalso include graphical representations of instruments that are insertedin the patient's head (H), such as navigation guidewire (40), such thatthe operator may view the virtual rendering of the instrument at itsactual location in real time. By way of example only, display screen(16) may provide images in accordance with at least some of theteachings of U.S. Pub. No. 2016/0008083, entitled “Guidewire Navigationfor Sinuplasty,” published Jan. 14, 2016, the disclosure of which isincorporated by reference herein. In the event that the operator is alsousing an endoscope, the endoscopic image may also be provided on displayscreen (16).

The images provided through display screen (16) may help guide theoperator in maneuvering and otherwise manipulating instruments withinthe patient's head (H) when such instruments incorporate navigationguidewire (40). It should also be understood that other components of asurgical instrument and other kinds of surgical instruments, asdescribed below, may incorporate a sensor like the sensor of navigationguidewire (40).

Endoscope with Single Camera 3D Imaging

FIG. 8 shows an exemplary endoscope (100) usable with a surgerynavigation system or other surgical system such as the IGS navigationsystem (10), in accordance with an embodiment of the present invention.The endoscope (100) includes a body (102) that may be gripped duringuse. A set of controls (103) are positioned at the distal end of body(102). A shaft (104) extends distally from the body (102). Shaft (104)includes a flex portion (108) and a distal tip (106). As will bedescribed in greater detail below, distal tip (106) may include one ormore features such as a camera, a light source, irrigation and suction,and/or channels through which flexible tools may be deployed. Theendoscope (100) also includes a position sensor (110) located betweenflex portion (108) and distal tip (106). Position sensor (110) maycomprise one or more coils that are configured to generate positionindicative signals in response to an alternating electromagnetic fieldgenerated by field generators (24), such that navigation system (10) maytrack the three-dimensional position of distal tip (106) within the head(H) of the patient (P) in real time, similar to the position tracking ofnavigation guidewire (40) described above.

Controls (103) are operable to drive rotation of shaft (104) about thelongitudinal axis of shaft (104). Controls (103) are also operable todrive deflection of distal tip (106) away from the longitudinal axis ofshaft (104) at flex portion (108). By way of example only, controls(103) may be configured and operable in accordance with at least some ofthe teachings of U.S. Pub. No. 2019/0015645, entitled “AdjustableInstrument for Dilation of Anatomical Passageway,” published Jan. 17,2019, the disclosure of which is incorporated by reference herein. Byway of further example only, endoscope (100) may also include one ormore controls for activating features of the endoscope (100); or foradvancing, withdrawing, and rotating flexible tools deployed to asurgical site via the endoscope (100).; and/or various other kinds ofcontrols as will be apparent to those skilled in the art in view of theteachings herein.

FIGS. 9A and 9B each show an exemplary distal tip (300) that may beutilized as the distal tip (106) of the endoscope (100), in accordancewith embodiments of the present invention. The distal tip (300) may bestatically positioned at the distal end of the shaft (104); or may bepositioned at a distal end of a flexible or deflectable shaft thatextends from or may be advanced and withdrawn through a channel of thedistal tip (106). The distal tip (300) includes an instrument channel(302), through which flexible instruments and tools may be deployedthrough once the distal tip (300) is positioned at a desired location.By way of example only, channel (302) may be sized to accommodate adilation catheter, a shaving instrument, an ablation instrument, and orvarious other kinds of instruments as will be apparent to those skilledin the art in view of the teachings herein. The distal tip (300) alsoincludes a wavefront imaging device (304) and a set of lights (306)(e.g., LED, fiber optic, infrared light sources, etc.). The distal tip(300) also includes a set of irrigation diverters (308). Each irrigationdiverter (308) is positioned proximately to a corresponding irrigationchannel (e.g., the irrigation channel (310) visible in FIGS. 10A and10B, which each show the distal tip (300) with one or both irrigationdiverters (308) removed). Irrigation diverters (308) are adapted toreceive and direct water or other liquids from the irrigation channel(310) to wash the wavefront imaging device (304), the lights (306), orboth.

The wavefront imaging device (304) may comprise a digital camera (e.g.,one or more image sensors) or imaging device capable of capturing andtransmitting image data to the processor (12); or another device of theIGS navigation system (10) capable of storing and processing the imagedata to generate 3D image data. While some conventional 3D image capturedevices may require two or more offset imaging devices that are capableof actively and independently focusing on a target, the wavefrontimaging device (304) of the present example is capable of producing 3Dimage data from a single camera or image sensor using wavefront samplingtechniques. In order to produce image data compatible with wavefrontsampling techniques, the wavefront imaging device (304) includes one ormore apertures that are positioned between the target and the cameralens; and that are off-axis or offset from the optical axis of the lens.When a target is imaged with the wavefront imaging device (304), asingle image will be produced that will contain multiple unfocuseddepictions of the target, offset from each other based upon thepositions of the aperture(s). The distance between each unfocused imagemay be used to calculate the depth or distance to the imaged target.Images captured by the wavefront imaging device (304) may be provided asinput to a wavefront sampling algorithm, such as Frigerio's multi imageprocedure, in order to produce a 3D depth map and 3D model of the imagedobject.

FIG. 11 shows one example of the wavefront imaging device (304), whichimplements a static optical system (320), in accordance with anembodiment of the present invention. The static optical system (320)includes a lens (326) with a first static aperture (328 a) and a secondstatic aperture (328 b) positioned between the lens (326) and a target(330). The apertures (328 a, 328 b) are diametrically opposed and offsetfrom the optical axis of the lens (326). Two or more apertures may beused, with a larger number of apertures improving accuracy of theresulting 3D image, while requiring additional time for imaging of atarget and processing of image data. A lower number of apertures mayreduce the time required for imaging and processing, in exchange for aloss of accuracy of the resulting 3D image. Aperture size may beincreased or decreased in order control the depth of field of capturedimages. Reducing the distance between the apertures and the lens (326)may also produce improved results for wavefront sampling.

During imaging, the lens (326) will receive a first unfocused image (332a) and a second unfocused image (332 b) of the target (330) through theapertures (328 a, 328 b), and will direct the first unfocused image (332a) and the second unfocused image (332 b) onto the image plane (322).The image plane (322) may be provided by a CCD, CMOS, or other imagesensor. An image offset (336) between the resulting images (332 a, 332b) may then be determined and used as part of a wavefront samplingtechnique to determine pixel depth and produce a 3D model of the target(330).

FIG. 12 shows another example of the wavefront imaging device (304),implemented as an active optical system (340), in accordance with anembodiment of the present invention. The active optical system (340)includes the lens (326) with a single aperture (344 a) positioned on arotatable aperture plate (342) between the lens (326) and the target(330). The aperture plate (342) may be electronically and automaticallyrotated during imaging in order to move the single aperture (344 a) fromits shown position, to a second position (344 b), a third position (344c), and so on throughout the rotation. In this example, the apertureplate (342) rotates about a rotation axis that is coaxial with theoptical axis of lens (326). As with the static optical system (320), thelens (326) receives unfocused images of the target (330) during rotationof the aperture plate (342). Thus, a first unfocused image (346 a), asecond unfocused image (346 b), a third unfocused image (346 c), and soon are projected onto the image plane (322) at offset positionsfollowing a rotation path (348). This image data captured by the imageplane (322) may then be used with wavefront sampling techniques todetermine pixel depth produced a 3D model of the target (330).

FIG. 13 depicts a set of exemplary steps (400) that may be performed toproduce a three-dimensional image model using an imaging device such asthe imaging device (304), in accordance with an embodiment of thepresent invention. Image data may be captured (block 402) as describedabove in the context of FIGS. 11 and 12 and processed into 3D image databy applying a wavefront sampling algorithm (e.g., Frigerio's multi imageprocedure or another similar algorithm). As an example, such a processmay include defining (block 404) an anchor image to use as a basis fordetermining offsets of the other images. The anchor image may be anarbitrarily selected image, an image that is most centrally locatedrelative to two or more other images; or may be selected based uponother criteria. An optical flow approach may then be used to calculatepixel displacement (block 406) between the anchor image and otherimages. A circle may be fit (block 408) to points across the images, andthe rotational diameter (or other offset value) may be determined (block410). The rotational diameter may then be used to calculate (block 412)pixel depth for a plurality of pixels of the image. Pixel depth may thenbe used to build (block 414) a 3D model of imaged object or target.

The distal tip (300) and wavefront imaging device (304) may beadvantageous in that they provide a solution for 3D imaging of asurgical site that has a relatively low complexity (e.g., as compared toa 3D camera with multiple independently and actively oriented cameras);and that can be mounted on the end of an instrument such as at thedistal tip (106), or that can be mounted on a flexible or deflectableshaft. Advantages in reduced complexity may be particularly realizedwhen the wavefront imaging device (304) is implemented with the staticoptical system (320), which can be implemented with a small physicalsize requirement and minimal supporting requirements due to low poweruse and lack of moving components (e.g., such as the aperture plate(342) or independently orientable cameras).

As noted above, endoscope (100) of the present example includes aposition sensor (110) that is operable to provide signals indicating thereal time position of distal tip (106) in three-dimensional space. Asimaging device (304) captures images, the image data from imaging device(304) may be stored in connection with the position data from positionsensor (110), such that IGS navigation system (10) (and/or some othercomputer system) may correlate each captured image with itscorresponding location in three-dimensional space. This will enable IGSnavigation system (10) to correlate images captured with imaging device(304) with one or more preoperatively obtained images (e.g., a CT or MRIscan, 3-D map, etc.). This aspect of the invention along with the dualcamera 3D imaging below can be used with the image correction aspect ofthe invention described above.

Endoscope with Dual Camera 3D Imaging

FIGS. 14A and 14B each show another exemplary distal tip (500) that maybe utilized as the distal tip (106) of the endoscope (100), inaccordance with other embodiments of the present invention. The distaltip (500) may be statically positioned at the distal end of the shaft(104); or may be positioned at a distal end of a flexible or deflectableshaft that extends from or may be advanced and withdrawn through achannel of the distal tip (106). The distal tip (500) includes aninstrument channel (502), having similar features and function as theinstrument channel (302); a light (506), having similar features andfunction as the light (306); and a set of irrigation channels (510),having similar features and function as the irrigation channels (310).The distal tip (500) also includes a first imaging device (504 a) and asecond imaging device (504 b), which may comprise digital cameras (e.g.,one or more image sensors) or other digital imaging devices capable ofcapturing image data at the distal tip (500) and transmitting it via ashaft or flexible shaft to the processor (12), coupling unit (42), oranother device of the IGS navigation system (10) capable of processingcaptured images. With reference to FIG. 8B, it can be seen that theimaging devices (504 a, 504 b) are offset from each other along a firstdimension (512), and at the same position along a second dimension(514).

FIGS. 15A and 15B show diagrammatic views of the distal tip (500) beingused to image a target with passive stereo vision, a triangulationmethod that uses two or more imaging devices to obtain images from twoor more different perspectives, in accordance with embodiments of thepresent invention. Images produced with passive stereo vision may betransformed into 3D image data algorithms such as a photogrammetricalgorithm that determines pixel depth based on epipolar geometry. InFIG. 15A, it can be seen that the first imaging device (504 a) and thesecond imaging device (504 b) are arranged on the distal tip (500) suchthat they have parallel optical axes. When directed at a target (520),the first imaging device (504 a) will capture a first field of view(522) of the target (520) while the second imaging device (504 b) willcapture a second field of view (526) of the target (520).

Since the two imaging devices (504 a, 504 b) have parallel optical axes(e.g., rather than independently focusing or orienting towards aconverging point), the images captured by the devices may contain anoverlapping portion of the target (520). For example, FIGS. 15A and 15Bshow the first field of view (522) and the second field of view (526),as well as a shared field of view (524), in which the target (520) willbe captured by both imaging devices. With reference to FIG. 15B, it canbe seen that the target (520) is substantially centered within theshared field of view (524). However, the target (520) is positioned onthe right side of the first field of view (522), and on the left side ofthe second field of view (526). This disparity, or the distance that thetarget (520) is offset or displaced from the first field of view (522)to the second field of view (526), can be used to determine the distancebetween the imaging device and the target, and then the depth of pixelsor portions of the captured image.

Determining and using disparity to determine depth is an example ofpassive triangulation. FIG. 16 depicts a set of exemplary steps (600)that may be performed to apply passive triangulation to image data, inaccordance with an embodiment of the present invention. Image data maybe captured (block 602) of a target by two or more statically arrangedcameras, such as the first imaging device (504 a) and the second imagingdevice (504 b), resulting in two distinct images of the target from twodifferent positions. A point (e.g., one or more pixels or portions of animage) may be picked (block 604) within one image, and the second imagewill be searched for a matching point (e.g., a portion of a target, suchas the target (520), that are shared between the two images asillustrated in FIG. 9B). Performing image analysis of a point within afirst image to find a matching point within an entirety of a secondimage may be both inefficient and inaccurate, resulting in a highprocessing requirement and an increased likelihood of false positivematching.

To improve the speed and accuracy of matching, the characteristics of anepipolar line associated with the two images may be determined (block606). Epipolar geometry is a concept that may be applied to two imagescaptured by cameras having a parallel optical axis in order to determinethe disparity or distance between two matching pixels or points in animage without searching the entirety of an image for a match. FIGS. 17and 19 depict diagrams illustrating the use of Epipolar geometry instereo imaging, in accordance with embodiments of the present invention.

With reference to FIG. 17 , which shows a diagram (700) that illustratesthe relationship between disparity (e.g., the distance between twomatching points in an image) and depth (e.g., the distance from thecamera to the target, or a pixel or point in the target), a first camera(704) and a second camera (706) are arranged such that they have aparallel optical axis (e.g., lines F-B and G-D) through their respectivelenses, which are arranged on the same lens plane (703). With thisarrangement, a target A (702) is within the field of view of eachcamera. The distance between the optical axis of the cameras is BC+CD,and the triangles ACB and BFE have similar characteristics but aredifferent in scale. Applying triangle geometry to FIG. 17 , thedisplacement between two matching points or pixels in an image can beexpressed as the distance between camera optical axes multiplied by thedistance from the lens plane (703) to the image sensor, divided by thedepth or distance to the target (702), or displacement=(BD*BF)/AC. Thisequation can be alternately used to determine or solve for the distanceto the target (702), or AC, after determining the displacement ordisparity.

To determine displacement between points or pixels in an image withoutsearching the entire image, principles of Epipolar geometry illustratedFIG. 18 can be applied. Since the cameras (704, 706) have a fixedposition relative to each other and parallel optical axes, an Epipolarline (712) can be determined that runs across a first image (708) and asecond image (710), along which matching points or pixels can be found.As a result, when matching a point on the first image (708) to a pointon the second image (710), only the portions of the second image (710)falling along the Epipolar line (712) need to be searched, rather thanthe entirety of the second image (710). By matching in this manner, thespeed and accuracy at which points can be matched across images may besignificantly increased.

After the points are matched (block 608), by applying Epipolar geometryor using another matching process, the displacement or disparity betweenmatched points may be determined (block 610), which may then be used todetermine (block 612) the depth or distance between the imaging deviceand the target. With the ability to determine (block 612) depth, a setof 3D image data and 3D model may be built (block 614).

As noted above, endoscope (100) of the present example includes aposition sensor (110) that is operable to provide signals indicating thereal time position of distal tip (106) in three-dimensional space. Asimaging devices (504 a, 504 b) capture images, the image data fromimaging devices (504 a, 504 b) may be stored in connection with theposition data from position sensor (110), such that IGS navigationsystem (10) (and/or some other computer system) may correlate eachcaptured image with its corresponding location in three-dimensionalspace. This will enable IGS navigation system (10) to correlate imagescaptured with imaging devices (504 a, 504 b) with one or morepreoperatively obtained images (e.g., a CT or MRI scan, 3-D map, etc.).

Method of Integrating 3D Imaging with Navigation

After producing 3D image data as described above, such image data can beused to provide additional features during IGS navigation. As anexample, FIG. 19 depicts a flowchart of a set of steps (800) that may beperformed to integrate a 3D model or 3D image data with IGS navigation,in accordance with an embodiment of the present invention. Aftercapturing (block 802) image data using an appropriate imaging module(e.g., the waveform imaging device (304) of the distal tip (300), theset of cameras (504 a, 504 b) of the distal tip (500)) and building(block 804) a 3D model or other 3D image data set, such data may be usedin various ways. For example, a composite image set may be created(block 806) by combining the 3D image data with other images, as well aswith data associating image sets with each other using location datasuch as position and orientation. This may include, for example,associating a built (block 804) 3D model with a set of preoperativelycaptured CT images, a set of 2D images captured with a position tracked2D endoscope during a procedure, or other similar information so thatmatching perspectives of a surgical site may be simultaneously displayedfrom multiple image sets.

As another example, a pre-operative comparison may be created (block808) which compares a preoperatively captured CT scan or other 3D modelwith the built (block 804) 3D model. This may be useful to aid inplanning or preparation for a surgical procedure, or to verify theaccuracy and configuration of one or more 3D models. For example, acomparison of the built (block 804) 3D model to a set of CT images mayhelp to identify missing or incorrect image or depth data in one or bothmodels, to identify incorrectly associated location data in one or bothmodels, or other errors that may be corrected by re-imaging to producenew 3D image data, or by reconfiguring or recalibrating to correctlocation data.

As another example, a post-operative comparison may be created (block810) which compares post procedure CT scan, 3D models, or other imagedata with a built (block 804) 3D model to aid in assessing the successof a surgical procedure. A 3D model built (block 804) pre-operativelymay be compared to a 3D model that is built (block 804) postoperatively; or may be compared to post-operative CT scans or 2D imagingof a surgical site. Such comparison data may aid a clinician to assessthe success or completeness of a surgical procedure, by physicallycomparing the anatomy from different perspectives available in 3Dimaging.

By way of further example only, 3D image data captured or otherwisegenerated using distal tip (200) or distal tip (300) may be utilized inaccordance with at least some of the teachings of U.S. ProvisionalPatent Application No. 62/782,608, entitled “3D Scanning of Nasal Tractwith Deflectable Endoscope,” filed Dec. 20, 2018, the disclosure ofwhich is incorporated by reference herein; U.S. Pat. No. 8,199,988,entitled “Method and Apparatus for Combining 3D Dental Scans with Other3D Data Sets,” issued Jun. 12, 2012, the disclosure of which isincorporated by reference herein; and/or “U.S. Pat. No. 8,821,158,entitled “Method and Apparatus for Matching Digital Three-DimensionalDental Models with Digital Three-Dimensional Cranio-Facial CAT ScanRecords,” issued Sep. 2, 2014, the disclosure of which is incorporatedby reference herein.

EXEMPLARY COMBINATIONS

The following examples relate to various non-exhaustive ways in whichthe teachings herein may be combined or applied. It should be understoodthat the following examples are not intended to restrict the coverage ofany claims that may be presented at any time in this application or insubsequent filings of this application. No disclaimer is intended. Thefollowing examples are being provided for nothing more than merelyillustrative purposes. It is contemplated that the various teachingsherein may be arranged and applied in numerous other ways. It is alsocontemplated that some variations may omit certain features referred toin the below examples. Therefore, none of the aspects or featuresreferred to below should be deemed critical unless otherwise explicitlyindicated as such at a later date by the inventors or by a successor ininterest to the inventors. If any claims are presented in thisapplication or in subsequent filings related to this application thatinclude additional features beyond those referred to below, thoseadditional features shall not be presumed to have been added for anyreason relating to patentability.

Example 1

A three-dimensional (3D) imaging system comprising: an endoscopecomprising: a shaft having a distal tip, the shaft adapted to beinserted into a patient and positioned at a surgical site of thepatient, a position sensor proximate to the distal tip and configured toproduce a set of position signals based on the location of the endoscopeduring use, and an imaging module positioned at the distal tip andoperable to capture a set of image data of the surgical site, whereinthe set of image data comprises one or more two-dimensional (2D) images;and a processor communicatively coupled with the endoscope andconfigured to: receive the set of image data and the set of positionsignals from the endoscope, determine a set of perspective data based onthe set of position signals, wherein the set of perspective dataindicates the location of the endoscope during capture of the set ofimage data, perform an image depth analysis to determine a set of 3Dcharacteristics of the set of image data, wherein the set of 3Dcharacteristics comprises a depth of pixels in the one or more 2Dimages, create a set of 3D image data based on the one or more 2D imagesand the set of 3D characteristics, and associate the set of perspectivedata with the set of 3D image data.

Example 2

The 3D imaging system of example 1, wherein the imaging modulecomprises: a single lens, an aperture plate positioned between a firstside of the single lens and the surgical site, the aperture platecomprising one or more apertures that are offset from the optical axisof the single lens, and an image pane positioned at a second side of thesingle lens to receive reflected light from the surgical site via theone or more apertures and the single lens, wherein the image pane isconfigured to produce the set of image data based on the reflectedlight.

Example 3

The 3D imaging system of example 2, wherein: the one or more aperturescomprise at least two apertures positioned on the aperture plate andoffset from the optical axis of the single lens, and the aperture platehas a fixed position and orientation relative to the lens.

Example 4

The 3D imaging system of any one or more of examples 2 through 3,wherein: the one or more apertures comprise a single aperture positionedon the aperture plate offset from the optical axis of the single lens,and the aperture plate is operable to rotate around its circular axisrelative to the lens during image capture.

Example 5

The 3D imaging system of any one or more of examples 2 through 4,wherein the processor is configured to, when performing the image depthanalysis: identify, within the set of image data, two or more unfocusedimages of the surgical site, determine a spatial relationship betweenthe two or more unfocused images of the surgical site, and determine thedepth of pixels of the set of image data based on the spatialrelationship between the two or more unfocused images.

Example 6

The 3D imaging system of any one or more of examples 1 through 5,wherein the imaging module comprises two or more cameras, and whereineach of the two or more cameras is: statically positioned relative toevery other camera of the two or more cameras, oriented to have aparallel optical axis with every other camera of the two or morecameras.

Example 7

The 3D imaging system of example 6, wherein the processor is furtherconfigured to, when performing the image depth analysis: identify apoint in a first image of the set of image data, wherein the pointcomprises a portion of the surgical site that is present within both thefirst image captured by a first camera of the two or more cameras andwithin a second image captured by a second camera of the two or morecameras, identify the point in the second image, determine adisplacement of the point from the first image to the second image, anddetermine the depth of pixels for the point based on the displacement.

Example 8

The 3D imaging system of example 7, wherein the processor is furtherconfigured to, when identifying the point in the second image: determinean Epipolar line for the first image and the second image based on thestatic position of the first camera relative to the second camera, andsearch for the point in the second image along the Epipolar line whileexcluding portions of the second image that do not fall along theEpipolar line.

Example 9

The 3D imaging system of any one or more of examples 1 through 8,wherein the processor is further configured to: associate the set of 3Dimage data and the set of perspective data with a coordinate system ofan image guided surgery system, and display the set of 3D image dataduring an image guided surgery navigation procedure based upon theassociation with the coordinate system.

Example 10

The 3D imaging system of any one or more of examples 1 through 9,wherein: the position sensor is configured to produce the set ofposition signals based on the location and orientation of the endoscopeduring use, the set of perspective data indicates the location andorientation of the endoscope during capture of the set of image data,and the processor is further configured to provide the set of 3D imagedata and the set of perspective data to an image guided surgerynavigation system.

Example 11

The 3D imaging system of any one or more of examples 1 through 10,wherein the processor is further configured to: receive an input from auser defining a perspective relative to the surgical site, determine afirst portion of the set of 3D image data depicting the surgical sitefrom the perspective based on identifying the perspective within the setof perspective data, and display the first portion of the set of 3Dimage data on a display.

Example 12

The 3D imaging system of example 11, wherein the processor is furtherconfigured to: receive an indirect 3D scan of the surgical site and aset of scan perspective data associated with the indirect 3D scan,determine a second portion of the indirect 3D scan depicting thesurgical site from the perspective based on identifying the perspectivewithin the set of scan perspective data, and display the first portionof the set of 3D image data and the second portion of the indirect 3Dscan on the display simultaneously.

Example 13

The 3D imaging system of example 12, wherein: the indirect 3D scan ofthe surgical site comprises pre-operatively captured image data, and theset of 3D image data comprises post-operatively captured image data.

Example 14

The 3D imaging system of any one or more of examples 12 through 13,wherein: the indirect 3D scan of the surgical site comprisespre-operatively captured image data, the set of 3D image data comprisespre-operatively captured image data, and the processor is furtherconfigured to: receive a scan adjustment input from a user, andreconfigure the association between the indirect 3D scan of the surgicalsite and the set of scan perspective data based on the scan adjustmentinput.

Example 15

A method for three-dimensional (3D) imaging comprising: deploying adistal tip of an endoscope to a surgical site of a patient, the distaltip comprising: an imaging module operable to capture image data of thesurgical site, wherein captured image data comprises one or moretwo-dimensional (2D) images, and a position sensor proximate to thedistal tip and configured to produce position signals based on thelocation of the endoscope; receiving a set of image data from theimaging module and a set of position signals from the position sensor;determining a set of perspective data based on the set of positionsignals, wherein the set of perspective data indicates the location ofthe endoscope during capture of the set of image data; performing animage depth analysis to determine a set of 3D characteristics of the setof image data, wherein the set of 3D characteristics comprises a depthof pixels in the one or more 2D images of the set of image data;creating a set of 3D image data based on the one or more 2D images ofthe set of image data and the set of 3D characteristics; and associatingthe set of perspective data with the set of 3D image data.

Example 16

The method of example 15, further comprising: associating the set of 3Dimage data and the set of perspective data with a coordinate system ofan image guided surgery system; and displaying the set of 3D image dataduring an image guided surgery navigation procedure based upon theassociation with the coordinate system.

Example 17

The method of any one or more of examples 15 through 16, furthercomprising: receiving an input from a user defining a perspectiverelative to the surgical site; determining a first portion of the set of3D image data depicting the surgical site from the perspective based onidentifying the perspective within the set of perspective data; anddisplaying the first portion of the set of 3D image data on a display.

Example 18

The method of example 17, further comprising: receiving an indirect 3Dscan of the surgical site and a set of scan perspective data associatedwith the indirect 3D scan; determining a second portion of the indirect3D scan depicting the surgical site from the perspective based onidentifying the perspective within the set of scan perspective data; anddisplaying the first portion of the set of 3D image data and the secondportion of the indirect 3D scan on the display simultaneously

Example 19

The method of example 18, further comprising: receiving a scanadjustment input from a user; and reconfiguring the association betweenthe indirect 3D scan of the surgical site and the set of scanperspective data based on the scan adjustment input; wherein: theindirect 3D scan of the surgical site comprises pre-operatively capturedimage data, and the set of 3D image data comprises pre-operativelycaptured image data.

Example 20

An image guided surgery (IGS) navigation system comprising a processor,a memory, and a display, the processor configured to: receive a set ofimage data produced by a tracked endoscope, the set of image datacomprising one or more two-dimensional (2D) images; receive a set ofperspective data produced by the tracked endoscope, wherein the set ofperspective data indicates a location of the tracked endoscope duringcapture of the set of image data; perform an image depth analysis todetermine a set of 3D characteristics of the set of image data, whereinthe set of 3D characteristics comprises a depth of pixels in the one ormore 2D images; create a set of 3D image data based on the one or more2D images and the set of 3D characteristics; associate the set ofperspective data with the set of 3D image data; and cause the display toshow the set of 3D image data from a selected perspective based on theset of perspective data including the selected perspective.

Example 21

A system, comprising: a medical probe configured to be inserted into acavity of an organ of a patient; a position and direction sensor in themedical probe operating in a sensor coordinate system; a camera in adistal edge of the medical probe operating in a sensor coordinatesystem; and a processor configured to: receive, from an imaging systemoperating in an image coordinate system, a three-dimensional image ofthe cavity comprising open space and organ tissue; receive, from themedical probe, signals indicating positions and respective directions ofthe distal edge of the medical probe inside the cavity; receive, fromthe camera of the probe, respective visualized locations inside thecavity; register the image coordinate system with the sensor coordinatesystem so as to identify one or more voxels in the three-dimensionalimage at the visualized locations; and when the identified voxels havedensity values in the received three-dimensional image that do notcorrespond to the open space, to update the density values of theidentified voxels to correspond to the open space.

Example 22

The system according to example 21, wherein the imaging system comprisesa computed tomography scanner.

Example 23

The system according to example 21, wherein the position and directionsensor comprises a magnetic field sensor.

Example 24

The system according to any of examples 21-23, wherein the processor isconfigured to form a correspondence between the density values visualeffects, wherein a given visual effect corresponds to a given densityvalue indicating the open space.

Example 25

The system according to example 24, wherein the visual effects areselected from a group consisting of colors, shadings and patterns.

Example 26

The system according to example 24, wherein the processor is configuredto present the three-dimensional image on a display using the visualeffects.

Example 27

The system according to example 26, wherein the given visual effectcomprises a first given visual effect, and wherein prior to updating thedensity values, the processor is configured to present thethree-dimensional image by presenting, using a second given visualeffect different from the first given visual effect, the one or moreidentified voxels.

Example 28

The system according to example 27, wherein upon updating the densityvalues, the processor is configured to present the three-dimensionalimage by presenting, using the first given visual effect, the one ormore identified voxels.

9.

Example 29

The system according to example 28, wherein the processor is configuredto, using a multi-view triangulation model, extract from the visualsignals a distance of a location from the camera.

Example 30

A method, comprising: receiving, from an imaging system operating in animage coordinate system, a three-dimensional image of a cavity of anorgan of a patient comprising open space and organ tissue; receiving,from a medical probe having a position and direction sensor and acamera, wherein the probe operates in a sensor coordinate system andinserted into the cavity: signals indicating positions and respectivedirections of a distal edge of the medical probe inside the cavity; andrespective visualized locations inside the cavity; registering the imagecoordinate system with the sensor coordinate system so as to identifyone or more voxels in the three-dimensional image at the visualizedlocations; and when the identified voxels have density values in thereceived three-dimensional image that do not correspond to the openspace, updating the density values of the identified voxels tocorrespond to the open space.

Example 31

A computer software product, operated in conjunction with a probe thatis configured for insertion into a cavity of an organ of a patient andincludes a position and direction sensor operating in a sensorcoordinate system and a camera in a distal edge of the medical probeoperating in a sensor coordinate system, and the product comprising anon-transitory computer-readable medium, in which program instructionsare stored, which instructions, when read by a computer, cause thecomputer to: receive, from an imaging system operating in an imagecoordinate system, a three-dimensional image of the cavity comprisingopen space and organ tissue; receive, from the medical probe, signalsindicating positions and respective directions of the distal edge of themedical probe inside the cavity; receive respective visualized locationsthe wall of the cavity; register the image coordinate system with thesensor coordinate system so as to identify one or more voxels in thethree-dimensional image at the visualized locations; and when theidentified voxels have density values in the received three-dimensionalimage that do not correspond to the open space, to update the densityvalues of the identified voxels to correspond to the open space.

Miscellaneous

While embodiments herein describe a processor using magnetic P&D sensingand optical visualization by a camera, applied to correct an outdated CTimage, using other types of position sensing, and visualization, tocorrect other types of medical images is considered to be within thespirit and scope of the present invention. For example, ultrasoundvisualization can be used with an ultrasound transducer instead of acamera. In addition, although the embodiments described herein mainlyaddress ENT procedures, the methods and systems described herein canalso be used in other applications, such as in other cavities of organsof the body.

It should be understood that any one or more of the teachings,expressions, embodiments, examples, etc. described herein may becombined with any one or more of the other teachings, expressions,embodiments, examples, etc. that are described herein. Theabove-described teachings, expressions, embodiments, examples, etc.should therefore not be viewed in isolation relative to each other.Various suitable ways in which the teachings herein may be combined willbe readily apparent to those skilled in the art in view of the teachingsherein. Such modifications and variations are intended to be includedwithin the scope of the claims.

It should be appreciated that any patent, publication, or otherdisclosure material, in whole or in part, that is said to beincorporated by reference herein is incorporated herein only to theextent that the incorporated material does not conflict with existingdefinitions, statements, or other disclosure material set forth in thisdisclosure. As such, and to the extent necessary, the disclosure asexplicitly set forth herein supersedes any conflicting materialincorporated herein by reference. Any material, or portion thereof, thatis said to be incorporated by reference herein, but which conflicts withexisting definitions, statements, or other disclosure material set forthherein will only be incorporated to the extent that no conflict arisesbetween that incorporated material and the existing disclosure material.

Versions of the devices disclosed herein can be designed to be disposedof after a single use, or they can be designed to be used multipletimes. Versions may, in either or both cases, be reconditioned for reuseafter at least one use. Reconditioning may include any combination ofthe steps of disassembly of the device, followed by cleaning orreplacement of particular pieces, and subsequent reassembly. Inparticular, versions of the device may be disassembled, and any numberof the particular pieces or parts of the device may be selectivelyreplaced or removed in any combination. Upon cleaning and/or replacementof particular parts, versions of the device may be reassembled forsubsequent use either at a reconditioning facility, or by a surgicalteam immediately prior to a surgical procedure. Those skilled in the artwill appreciate that reconditioning of a device may utilize a variety oftechniques for disassembly, cleaning/replacement, and reassembly. Use ofsuch techniques, and the resulting reconditioned device, are all withinthe scope of the present application.

By way of example only, versions described herein may be processedbefore surgery. First, a new or used instrument may be obtained and ifnecessary cleaned. The instrument may then be sterilized. In onesterilization technique, the instrument is placed in a closed and sealedcontainer, such as a plastic or TYVEK bag. The container and instrumentmay then be placed in a field of radiation that can penetrate thecontainer, such as gamma radiation, x-rays, or high-energy electrons.The radiation may kill bacteria on the instrument and in the container.The sterilized instrument may then be stored in the sterile container.The sealed container may keep the instrument sterile until it is openedin a surgical facility. A device may also be sterilized using any othertechnique known in the art, including but not limited to beta or gammaradiation, ethylene oxide, or steam.

Having shown and described various versions of the present invention,further adaptations of the methods and systems described herein may beaccomplished by appropriate modifications by one skilled in the artwithout departing from the scope of the present invention. Several ofsuch potential modifications have been mentioned, and others will beapparent to those skilled in the art. For instance, the examples,versions, geometrics, materials, dimensions, ratios, steps, and the likediscussed above are illustrative and are not required. Accordingly, thescope of the present invention should be considered in terms of thefollowing claims and is understood not to be limited to the details ofstructure and operation shown and described in the specification anddrawings.

1-31. (canceled)
 32. An apparatus, comprising: (a) a shaft having adistal tip, the shaft adapted to be inserted into a patient andpositioned at a surgical site of the patient; (b) a passive stereovision device positioned at the distal tip and operable to capture a setof image data comprising one or more two-dimensional (2D) images,wherein the passive stereo vision device comprises two or more cameras,wherein each camera of the two or more cameras are: (i) staticallypositioned relative to every other camera of the two or more cameras,and (ii) oriented to have a parallel optical axis with every othercamera of the two or more cameras; and (c) a channel extending throughthe shaft and to the distal tip, the channel being configured to provideone or more of: (i) passage of a working instrument, or (ii)communication of a fluid.
 33. The apparatus of claim 32, wherein the twoor more cameras of the passive stereo vision device are offset from eachother along a first dimension and are at a same position as each otheralong a second dimension.
 34. The apparatus of claim 32, wherein the twoor more cameras of the passive stereo vision device are configured tocapture two or more fields of view of the surgical site, respectively,wherein the two or more fields of view overlap each other.
 35. Theapparatus of claim 32, wherein the two or more cameras of the passivestereo vision device have two or more lenses arranged on a same lensplane as each other.
 36. The apparatus of claim 32, wherein the shaft isoperable to provide deflection of the distal tip.
 37. The apparatus ofclaim 32, wherein the distal tip includes at least one illuminatingelement configured to illuminate at least one field of view of thepassive stereo vision device.
 38. The apparatus of claim 32, furthercomprising at least one irrigation diverter configured to direct atleast a portion of irrigation fluid from the channel to the passivestereo vision device.
 39. The apparatus of claim 32, further comprisinga position sensor proximate to the distal tip and configured to producea set of position signals based on a location of the apparatus duringuse.
 40. A three-dimensional (3D) imaging system comprising: (a) theapparatus of claim 32; and (b) a processor communicatively coupled withthe apparatus and configured to perform an image depth analysis todetermine a set of 3D characteristics for each of the one or more 2Dimages, wherein the image depth analysis comprises a passive stereovision technique.
 41. A three-dimensional (3D) imaging systemcomprising: (a) an endoscope comprising: (i) a shaft having a distaltip, the shaft adapted to be inserted into a patient and positioned at asurgical site of the patient, and (ii) a passive stereo vision devicepositioned at the distal tip and operable to capture a set of image datacomprising one or more two-dimensional (2D) images, wherein the passivestereo vision device comprises two or more cameras, wherein each of thetwo or more cameras are: (A) statically positioned relative to everyother camera of the two or more cameras, and (B) oriented to have aparallel optical axis with every other camera of the two or morecameras; and (b) a processor communicatively coupled with the endoscopeand configured to: (i) receive the set of image data from the endoscope,and (ii) perform an image depth analysis to determine a set of 3Dcharacteristics for each of the one or more 2D images, wherein the setof 3D characteristics comprises a depth of pixels, wherein the imagedepth analysis comprises a passive stereo vision technique comprising:(A) identifying a point in a first image of the set of image data,wherein the point comprises a portion of the surgical site that ispresent within both the first image captured by a first camera of thetwo or more cameras and within a second image captured by a secondcamera of the two or more cameras, (B) identifying the point in thesecond image, (C) determining a displacement of the point from the firstimage to the second image, and (D) determining the depth of pixels forthe point based on the displacement.
 42. The 3D imaging system of claim41, wherein the processor is further configured to, when identifying thepoint in the second image, determine an Epipolar line for the firstimage and the second image based on the static position of the firstcamera relative to the second camera.
 43. The 3D imaging system of claim42, wherein the processor is further configured to, when identifying thepoint in the second image, search for the point in the second imagealong the Epipolar line while excluding portions of the second imagethat do not fall along the Epipolar line.
 44. The 3D imaging system ofclaim 41, wherein the processor is further configured to create a set of3D image data based on the one or more 2D images and the set of 3Dcharacteristics.
 45. The 3D imaging system of claim 44, wherein theendoscope further comprises a position sensor proximate to the distaltip and configured to produce a set of position signals based on alocation of the endoscope during use, wherein the processor is furtherconfigured to: (i) receive the set of position signals from theendoscope, (ii) determine a set of perspective data based on the set ofposition signals, wherein the set of perspective data indicates thelocation of the endoscope during capture of each of the one or more 2Dimages, (iii) receive an input from a user defining a perspectiverelative to the surgical site, (iv) determine a first portion of the setof 3D image data depicting the surgical site from the perspective basedon identifying the perspective within the set of perspective data, and(v) display the first portion of the set of 3D image data on a display.46. The 3D imaging system of claim 45, wherein the processor is furtherconfigured to: (i) receive an indirect 3D scan of the surgical site anda set of scan perspective data associated with the indirect 3D scan,(ii) determine a second portion of the indirect 3D scan depicting thesurgical site from the perspective based on identifying the perspectivewithin the set of scan perspective data, and (iii) display the firstportion of the set of 3D image data and the second portion of theindirect 3D scan on the display simultaneously.
 47. The 3D imagingsystem of claim 46, wherein the indirect 3D scan of the surgical sitecomprises pre-operatively captured image data.
 48. The 3D imaging systemof claim 47, wherein the set of 3D image data comprises post-operativelycaptured image data.
 49. The 3D imaging system of claim 47, wherein theset of 3D image data comprises pre-operatively captured image data. 50.The 3D imaging system of claim 49, wherein the processor is furtherconfigured to: (i) receive a scan adjustment input from a user, and (ii)reconfigure the association between the indirect 3D scan of the surgicalsite and the set of scan perspective data based on the scan adjustmentinput.
 51. A method for three-dimensional (3D) imaging comprising: (a)deploying a distal tip of an endoscope to a surgical site of a patient,the distal tip comprising a passive stereo vision device operable tocapture image data comprising one or more two-dimensional (2D) images,wherein the passive stereo vision device comprises two or more cameras,wherein each of the two or more cameras are statically positionedrelative to every other camera of the two or more cameras and orientedto have a parallel optical axis with every other camera of the two ormore cameras; (b) receiving a set of image data from the passive stereovision device; and (c) performing an image depth analysis to determine aset of 3D characteristics for each of the one or more 2D images, whereinthe set of 3D characteristics comprises a depth of pixels, wherein theimage depth analysis comprises a passive stereo vision techniquecomprising: (i) identifying a point in a first image of the set of imagedata, wherein the point comprises a portion of the surgical site that ispresent within both the first image captured by a first camera of thetwo or more cameras and within a second image captured by a secondcamera of the two or more cameras, (ii) identifying the point in thesecond image, (iii) determining a displacement of the point from thefirst image to the second image, and (iv) determining the depth ofpixels for the point based on the displacement.